From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 028B3C43603 for ; Thu, 19 Dec 2019 20:22:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CABB32467E for ; Thu, 19 Dec 2019 20:22:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576786945; bh=7oErwg8eizJPySOsvAiJP6DiMFCPLi+VkoQygK3pyX4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pG5wKVHDCZu/VYhEUByER5JjMtfYJyIZ/i7dE7TPzqHvneDloNBSKa/HVl3uwX5QO OTK0VawDm5/Jl34PpZQ2xSIHPyRogdD6UJ5WvGo5bYkrePST2bUF+Yggp3zOG/1Zgp E0cvR4Tccl1BUljgMA1n95E/kpLjFf2tctxA8by4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbfLSUWZ (ORCPT ); Thu, 19 Dec 2019 15:22:25 -0500 Received: from mail-qk1-f196.google.com ([209.85.222.196]:35366 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727386AbfLSUWP (ORCPT ); Thu, 19 Dec 2019 15:22:15 -0500 Received: by mail-qk1-f196.google.com with SMTP id z76so6102562qka.2; Thu, 19 Dec 2019 12:22:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=r3E/D07/ZPDWwCmYCAV3wbix4nrV2NEeuAgSXWyKjuk=; b=u6Wv8j6rmYawNkXdt1PMu7j72pvZx7svOC3E6pznjHc7+FKrdLbnpmSkSLwC619uwG SIgEtVQR3RNyDP+MnUu66RibgcVwqQX/7rUtScjLHr6Pal8yn5U7QlcAesErCFSx45hg onib1uCCGQGQadOVJ+9ENHyQPk7xutFYx7b1zOF5X0rBodDabJl+LlsmlqIuIykD/DzO MOmBK1o41B4picUTKElrG4ixXSjCjS7NnbUTWFBfd3+qZfRpJHnl1AFp7qvXMZxle2rU 17vEUZKBjvL3LIfCGY1R9UbjtXkIr9KX9urMGHHKJB+HfnE4pxaih6aOzIYdxGCeXAuG GRzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=r3E/D07/ZPDWwCmYCAV3wbix4nrV2NEeuAgSXWyKjuk=; b=rwEoMk+gS2ANdTYlTeJspJ1zHZzEZEelPLOfki4YOSjl2m7PdrNSu+mf/9cA0hcocC vBzoRqVcO+uiBOdq2GCJsHdXnkQEq5zZckJmvxSCD7oN2C6sNtZkucM0eteHz2XEtm/g i5rD2ds41uUxEOET5++IXylw+GPQ/4pWdOP12CvPVCKDXf456rRHIZMGbqKl0g33kQUT QvQba+swYiPSN5uH6G42HgbKt0EsBT6rus3NS7a/Yl9p+8Sh2xXktKKXU7OByZFR+STd SM65c1hu4xuD8977V8K+HGrW2DQV1lA3N1w7Qh6dEEFFbxPDuKkL3TM1RVKXD1+xg6Q5 NbNw== X-Gm-Message-State: APjAAAV0k/hE9goMpZVZaqYFxMCGSy+tlCfD9IQ8rh4tCSFrOqE9iWVP D75yvgibXqwUc6GS4cLRqwHJFCGVzNI= X-Google-Smtp-Source: APXvYqwjzlfu4HM0DKELI9BComNmyS8fALsw5Qp8Q5/Hv7wFJLwaM5FyiCgJ4C2p0Cv1SU6/gb4l9w== X-Received: by 2002:a37:de05:: with SMTP id h5mr10251127qkj.474.1576786934078; Thu, 19 Dec 2019 12:22:14 -0800 (PST) Received: from localhost ([2620:10d:c091:500::1:29ea]) by smtp.gmail.com with ESMTPSA id z28sm2280778qtz.69.2019.12.19.12.22.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Dec 2019 12:22:13 -0800 (PST) Date: Thu, 19 Dec 2019 12:22:11 -0800 From: Tejun Heo To: Johannes Weiner Cc: Andrew Morton , Roman Gushchin , Michal Hocko , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH v2 0/3] mm: memcontrol: recursive memory protection Message-ID: <20191219202211.GD2914998@devbig004.ftw2.facebook.com> References: <20191219200718.15696-1-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191219200718.15696-1-hannes@cmpxchg.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 19, 2019 at 03:07:15PM -0500, Johannes Weiner wrote: > Changes since v1: > - improved Changelogs based on the discussion with Roman. Thanks! > - fix div0 when recursive & fixed protection is combined > - fix an unused compiler warning > > The current memory.low (and memory.min) semantics require protection > to be assigned to a cgroup in an untinterrupted chain from the > top-level cgroup all the way to the leaf. > > In practice, we want to protect entire cgroup subtrees from each other > (system management software vs. workload), but we would like the VM to > balance memory optimally *within* each subtree, without having to make > explicit weight allocations among individual components. The current > semantics make that impossible. Acked-by: Tejun Heo The original behavior turned out to be a significant source of mistakes and use cases which would require older behavior just weren't there. Thanks. -- tejun